1. Field of the Invention
The present invention relates to a method of controlling a pulsed light source that amplifies pulsed light outputted from a directly modulated semiconductor laser by an optical fiber amplifier, and repeatedly outputs the amplified pulsed light.
2. Related Background Art
A pulsed light source is used for industrial applications represented by laser processing. Generally for processing micro-objects by laser, it is critical to control a pulse width of a pulsed laser beam to be constant, in order to manage processing quality, including a thermal effect on surroundings. On the other hand, throughput or the like demanded for each processing object varies, and a repetition frequency of the pulsed light output must be optimized according to the application. Control of a pulse width is important not only for micro-processing, but also for optical measurement, communication and medical application fields. Japanese Patent Application Laid-Open No. 2009-152560 (Patent Document 1) discloses an invention to compress a pulse width of an output pulsed light.